Blood pressure is an important health indicator and is measured using two numbers – the systolic pressure (top number) and the diastolic pressure (bottom number). The systolic pressure measures the pressure in the arteries when the heart beats, while the diastolic pressure measures the pressure between heartbeats. A normal blood pressure is less than 120/80 mmHg. If the diastolic pressure is consistently above 80 mmHg, it is considered high. High diastolic blood pressure signifies that the blood vessels are under increased pressure even when the heart is resting between beats. If left uncontrolled, it can lead to serious health complications. Understanding what causes high diastolic pressure is key to managing and reducing it.
What is Diastolic Blood Pressure?
Diastolic blood pressure refers to the pressure in the blood vessels when the heart muscle is resting between beats. It is represented by the bottom number in a blood pressure reading. Normal diastolic blood pressure is less than 80 mmHg. When the diastolic pressure is between 80-89 mmHg, it is considered elevated. A reading of 90 mmHg or higher is considered high.
During the diastolic phase, the heart fills with blood after ejecting blood into the circulation during systole. The diastolic pressure indicates the minimum pressure needed to keep blood circulating between heartbeats. Higher diastolic pressure suggests the blood vessels have an elevated resistance to blood flow.
Significance of Diastolic Blood Pressure
Diastolic pressure provides important information about the state of the blood vessels and the ease of blood flow in the circulatory system. Chronically high diastolic pressure can have the following implications:
- Increased workload on the heart as it has to pump against higher pressure
- Hardening and loss of elasticity of the blood vessel walls
- More strain on the delicate tissues of the kidneys and eyes
- Higher risk of heart attack, stroke, and kidney disease
Therefore, maintaining a normal diastolic pressure is key to vascular and overall health. Understanding the various causes of elevated diastolic pressure can help gain better control over blood pressure.
Causes of High Diastolic Blood Pressure
There are several factors that can lead to an increase in diastolic blood pressure. The main causes include:
Aging
As people age, the blood vessels tend to stiffen and lose elasticity. This increases resistance to blood flow and causes an elevation in diastolic pressure. Aging is one of the most common reasons for isolated high diastolic pressure in older adults.
Genetics
Some individuals may have a genetic predisposition to developing high blood pressure. Family history is a major risk factor for hypertension. Mutations in certain genes that regulate blood pressure can cause elevated diastolic pressure.
Being Overweight/Obesity
Carrying excess weight puts additional pressure on the blood vessels and the heart. It can accelerate blood vessel damage and the aging process, resulting in stiffening of arteries. This greatly contributes to high diastolic pressure in overweight and obese individuals. Losing weight helps reduce blood pressure.
Insulin Resistance/Diabetes
Insulin resistance impairs the transportation of glucose out of the bloodstream and into cells. This causes high blood glucose levels, which can damage blood vessels and cause them to constrict. This increases diastolic pressure. High blood glucose also makes vessels stiff and less elastic. Diabetes further aggravates these effects.
High Salt Intake
Consuming too much sodium causes fluid retention, making blood vessels stiffer and narrower. This directly increases blood pressure. Reducing salt intake helps lower and control diastolic pressure.
Stress
Chronic stress stimulates the release of hormones like cortisol and adrenaline. These hormones can trigger vasoconstriction – narrowing of blood vessels. Frequent stress also accelerates the aging process. Both these effects contribute to elevated diastolic pressure.
Alcohol and Smoking
Excessive intake of alcohol and smoking damage blood vessels walls. They cause inflammation and tissue damage. This increases rigidity in vessels and resistance to blood flow, resulting in higher diastolic pressure.
Kidney Disease
Healthy kidneys regulate fluid balance in the body and produce hormones that influence blood pressure. Kidney diseases disrupt these mechanisms leading to fluid retention and stiff blood vessels. This drives up diastolic pressure.
Pregnancy
Some women can develop elevated blood pressure in pregnancy due to various factors like genetics, hormonal changes, etc. This is known as gestational hypertension and often resolves after delivery. But a subset may continue to have chronically high diastolic pressure postpartum.
Medications
Certain prescription medications like corticosteroids, birth control pills, decongestants, antidepressants, and pain relievers can raise blood pressure as a side effect. Checking with a doctor to switch medications can help reduce diastolic pressure caused by medications.
Obstructive Sleep Apnea
Sleep apnea causes interrupted breathing while sleeping. This stimulates the release stress hormones and deprives the body of oxygen. It also activates inflammatory pathways. These effects contribute to blood vessel changes that increase diastolic pressure.
Thyroid Disorders
Both hypothyroidism and hyperthyroidism affect the heart and blood vessels in ways that can raise diastolic pressure. Getting thyroid levels tested and corrected helps normalize blood pressure.
Adrenal Disease
Disorders affecting the adrenal glands like Cushing’s syndrome, pheochromocytoma, and adrenal insufficiency influence blood pressure. Diagnosing and treating these conditions may lower elevated diastolic pressure.
Aortic Valve Stenosis
This disorder which narrows the aortic valve forces the heart to work harder to pump blood. This extra workload can increase diastolic pressure over time.
Risk Factors
Certain factors increase an individual’s risk of developing high diastolic blood pressure:
- Older age (over 65 years)
- Family history of hypertension
- Overweight or obesity
- Sedentary lifestyle
- High-sodium diet
- Excessive alcohol use
- Smoking
- High cholesterol
- Chronic stress
- Diabetes, insulin resistance, metabolic syndrome
- Kidney disease
- Sleep apnea
The more risk factors an individual has, the higher their risk of experiencing elevated diastolic pressure.
Dangers of High Diastolic Pressure
If high diastolic pressure is left uncontrolled, it can lead to:
- Thickening and damage of blood vessel walls
- Narrowing of arteries
- Increased risk of plaque formation and atherosclerosis
- Higher risk of heart attack and stroke
- Kidney damage and disease
- Retinal damage
- Fluid in lungs
- Enlarged heart and heart failure
- Brain damage from ruptured blood vessels
Therefore, prompt management of elevated diastolic pressure is critical to preserve health and prevent serious complications.
Diagnosis
High diastolic pressure is diagnosed through routine blood pressure checks. As per hypertension guidelines:
- Normal: Less than 80 mmHg
- Elevated: Between 80-89 mmHg
- Stage 1 Hypertension: Between 90-99 mmHg
- Stage 2 Hypertension: 100 mmHg or higher
To confirm a diagnosis of hypertension, elevated readings should be consistent over several blood pressure measurements over a few weeks.
Isolated diastolic hypertension is diagnosed when the diastolic pressure is high but systolic pressure is normal.
Doctors may recommend further testing to identify any underlying causes such as:
- Blood tests to check cholesterol, blood glucose, kidney function, electrolytes, thyroid function
- Urine test to assess kidney damage and disease
- EKG and echocardiogram to look for heart problems
- Stress testing of heart function
- CT scan of adrenal glands if adrenal disorders suspected
- Sleep study if sleep apnea suspected
- Ultrasound of kidneys
Treatment
The key goals in treating high diastolic pressure are:
- Lower diastolic pressure to less than 80 mmHg
- Control systolic pressure if elevated
- Reduce risk of heart disease, stroke, and kidney failure
- Prevent further vascular damage
Treatment options include:
Lifestyle Changes
- Weight loss if overweight
- Regular exercise – 30 mins most days of the week
- Limiting alcohol to 1 drink per day for women, 2 for men
- Eating a heart-healthy diet like the DASH diet
- Cutting back on sodium
- Quitting smoking and vaping
- Stress management through meditation, yoga etc.
- Treating underlying causes like sleep apnea
Medications
- ACE inhibitors like lisinopril, benazepril
- Angiotensin II receptor blockers like losartan, valsartan
- Calcium channel blockers like amlodipine, diltiazem
- Alpha blockers like prazosin
- Beta blockers like metoprolol
- Diuretics
Most people require a combination of 2 or more blood pressure medications to achieve adequate control, especially those with diabetes, kidney disease, or heart failure.
Home Monitoring
Home monitoring enables tracking response to therapy. Readings should be lower than 135/85 mmHg. Continued high readings indicate poor control and the need for medication adjustment.
Follow-Up
Follow up visits every 1-3 months to monitor blood pressure control, modify treatment and screen for organ damage are important. Annual kidney function tests, eye exams and blood glucose assessment are also recommended.
Prevention
Preventive strategies to maintain normal diastolic pressure include:
- Maintaining normal body weight
- Limiting sodium and alcohol intake
- Quitting smoking
- Exercising regularly – 150 minutes per week
- Following a healthy, balanced diet
- Managing stress effectively
- Taking medications correctly if prescribed
- Getting adequate sleep
- Annual check-ups to monitor blood pressure
Making healthy lifestyle choices can help prevent high diastolic pressure in those with risk factors.
Conclusion
High diastolic blood pressure significantly raises the risks of serious cardiovascular and kidney complications. Understanding the various causes and drivers of elevated diastolic pressure enables better management. A multipronged approach of lifestyle changes, medications, home monitoring and consistent follow up is key to lowering diastolic pressure and maintaining it within a healthy range. Implementing preventive strategies can help avoid developing high diastolic pressure in the first place. With proper control and management, individuals with elevated diastolic pressure can regain their health and avoid harmful consequences.